Bulk bag with forklift tine receiving elements and elements therefor

ABSTRACT

A bulk bag is provided of the type having flexible side walls; a bottom wall configured to define, with the sidewalls, a generally rectangular shape of bag; and a pair of laterally spaced generally parallel flexible sleeve formations associated with the bottom wall. Each of the sleeve formations operatively receives a generally rigid tubular element of generally rectangular cross-sectional configuration such that the two tubular elements may receive the tines of a forklift truck, in use. Each tubular element is composed of two operatively generally horizontal elongate channel shaped components each having a pair of opposed side flanges and a central web interconnecting the side flanges and wherein one channel shaped component is inverted relative to, and fits within, the other to define said tubular element that has a pair of opposed composite side walls each consisting of two overlapping side flanges. The side flanges of the channel shaped components preferably have a series of spaced parallel ribs or strengthening webs extending up the height of the channel from the central web to the free edges of the flanges thereof.

FIELD OF THE INVENTION

This invention relates to bulk bags of the type widely used for transporting bulk commodities from one place to another and wherein the filled bulk bags are often packed into shipping containers or closed road or rail transport vehicles (herein collectively referred to as transport containers). The bulk bags with which this invention is concerned include those termed flexible intermediate bulk containers and often referred to as FIBC. More particularly, the invention relates to bulk bags that have a pair of laterally spaced forklift tine receiving tubular elements in the bottom region thereof whereby the bulk bag can be moved and maneuvered using a forklift truck.

BACKGROUND TO THE INVENTION

Bulk bags are becoming increasingly popular for the purpose of transporting commodities that range from mined ores and minerals, in either granular or lumpy form, to agricultural products, chemicals, small hardware components and small packages of many different small products.

International patent publication number WO 2004/071874 sets out the advantages of providing forklift tine receiving tubular elements at the bottom of a bulk bag to enable the filled bag to be maneuvered using a forklift truck. That publication also discusses various proposals and itself describes a construction of tubular element that is particularly effective, especially as regards strength to weight of the tubular elements that must support at least a part of the weight of contents of the bulk bag at the lateral extremities. The description of that earlier published patent application is incorporated herein by reference.

During development of the construction described in that earlier patent publication a construction of the tubular elements has been developed that is particularly effective.

OBJECT OF THE INVENTION

It is an object of this invention to provide a bulk bag and, in particular, an alternative construction of tine receiving tubular elements therefor.

SUMMARY OF THE INVENTION

In accordance with one aspect of the invention there is provided a bulk bag having flexible side walls; a bottom wall configured to define, with the sidewalls, a generally rectangular shape of bag; and a pair of laterally spaced generally flexible sleeve formations associated with the bottom wall and each of which operatively receives a generally rigid tubular element of generally rectangular cross-sectional configuration adapted to receive a tine of a forklift truck, in use, the bulk bag being characterized in that each tubular element is composed of two operatively generally horizontal elongate channel shaped components each having a pair of opposed side flanges and a central web interconnecting the side flanges and wherein one channel shaped component is inverted relative to, and fits within, the other to define said tubular element that has a pair of opposed composite side walls each consisting of two overlapping side flanges.

Further features of this aspect of the invention provide for the side flanges of the channel shaped components to each have a series of spaced parallel ribs or strengthening webs extending up the height of the channel from the central web to the free edges of the flanges thereof; for each channel shaped component to be made from cut and folded sheet material that preferably consists of two spaced parallel walls interconnected by an intermediate core that defines a series of spaced parallel stiffening ribs or strengthening webs; for the intermediate core to be either a series of parallel webs of material that are integral with the two spaced parallel walls and are conveniently formed by extrusion of a suitable plastic material, typically a suitable polypropylene or polyethylene material or, in the alternative, for the intermediate core to be defined by one or more corrugated layers bonded to the two spaced parallel walls; for the corners of each channel to be defined by generally right angled folds in the sheet material wherein the folds extend at right angles to the series of parallel stiffening ribs or strengthening webs; in the event that the sheet is of plastics material, for the bends to be optionally formed by heat softening the material along the lines of the bends and allowing it to cool in the bent condition or by mechanical deformation along the bend lines; and for one end of each tubular element to have integral protective flange formations formed by bends in the material at right angles to the length of the rigid tubular element.

It is a particular feature of this aspect of the invention that the overlapping flanges of the two reversed channel shaped components be secured together, either temporarily or permanently, by any suitable means such as adhesive, solvent bonding, or, in appropriate circumstances, thermal welding of the flanges together at a predetermined plurality of sites, typically a plurality of “spots” spread over the area of overlapping of the flanges.

In accordance with a second aspect of the invention there is provided a rigid tubular element for a bulk bag generally as defined above, the rigid tubular element being made from one or more cut and folded sheets of material characterized in that the sheet material is a reconstituted fibre product, typically a paper or cardboard product.

In accordance with a third aspect of the invention there is provided a rigid tubular element suitable for installation in a flexible sleeve formation on a bulk bag in order to form a bulk bag as a defined above.

In accordance with a fourth aspect of the invention there is provided a knockdown tubular element in kit form and comprising one or two cut blanks of sheet material configured to define fold lines along which the material can be folded to form channel shaped components of a tubular element of rectangular shape in cross-section and that is suitable for installation in the flexible sleeves of a bulk bag as defined above.

Referring to the bulk bag defined above, the laterally spaced sleeves are preferably formed within the general rectangular shape of the bag such that, in use, the bottom of the bag between the sleeves is generally coplanar with a bottom wall of each of the spaced sleeves.

The bulk bag is, apart from the aforesaid unique features, made very much along conventional lines and typically of a suitable woven fabric of polypropylene, polyethylene, or polyester strands and mixtures thereof with assembly being carried out utilizing suitable stitching or thermal bonding techniques, or both. The bulk bag may also be provided with any conventional or other features such as a flexible top cover or a flexible funnel inlet at the top; a flexible tubular outlet at the bottom for discharging flowable contents as and when required; and additional lifting handles, typically at the corners.

In order that the above and other features of the invention may be more fully understood one embodiment thereof will now be described with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a schematic isometric illustration of a bulk bag according to the invention from the front, or “approach side” for a forklift truck and showing the front ends of the tubular elements;

FIG. 2 is a view taken in the same direction as FIG. 1 but of one embodiment of tubular element according to the invention;

FIG. 3 is an exploded front end view of the tubular element shown in FIG. 2;

FIG. 4 is a front view of the assembled tubular element;

FIG. 5 is a rear view of the assembled tubular element;

FIG. 6 is an isometric illustration of a small area of sheet material from which the tubular elements are made; and,

FIG. 7 is a plan view of a pair of cut and sulcated blank sheets of material prior to bending along the fold lines to form a pair of channel shaped components of the tubular element.

DETAILED DESCRIPTION WITH REFERENCE TO THE DRAWINGS

As indicated above the invention relates to a bulk bag of the type illustrated in FIG. 1 and generally indicated by numeral (1). The bag is made by substantially conventional manufacturing techniques of cutting and stitching and/or thermally bonding a suitable woven fabric material, typically a woven polypropylene or other suitable material. The bulk bag has sidewalls (2) and a bottom wall (3) that is adapted to rest on the ground or floor between two generally squat rectangular cross-sectioned tubular elements (5) that, in use are to receive the tines of a forklift truck. This arrangement results in the majority of the often substantial weight of a filled bag being exerted directly on the floor and only a minor portion being exerted on the tubular elements themselves.

In order to accommodate the tubular elements (5) there are formed two flexible sleeves (6) that extend generally parallel to each other, one in each corner of the bottom of the bag where the relevant side wall joins the bottom wall so as to extend from what is referred to herein as the front (7) of the bulk bag to what is referred to as the rear (8) thereof.

Each of the tubular elements (5) is made from two channel shaped components (9, 10), the one (9) of which is inverted and fits neatly within the other (10). Each of the tubular elements has a generally horizontal central web (11, 12) and a pair of flanges (13, 14) at right angles to the web (see in particular FIG. 5). The two flanges on each side of the composite tubular element overlap up the entire height of the flanges and the flanges are preferably secured together, at least for use. In the event that the channel shaped components are made of a plastics material they can conveniently be “spot welded” together at a series of positions spread over the area of the overlapping flanges, as indicated by numeral (15) in FIG. 2.

In one particular instance, the channel shaped components are each made by folding a flat sheet of extruded plastics material that preferably has a series of stiffening ribs or strengthening webs extending in the direction of extrusion and that are arranged to extend transverse to the length of the tubular element.

In this embodiment of the invention the extruded plastics sheet material (see FIG. 6) comprises a pair of spaced parallel walls (16) that are interconnected by a series of spaced parallel webs (17) of integral material that form a series of longitudinally extending cavities. A suitable sheet material is that termed “twin walled fluted cellular structural panel” whereof a polypropylene version is sold in South Africa under the trademarks CORREX™ and CORUPLAS™.

Alternatively, the sheet material could be a suitable fabricated sheet in which instance two spaced sheets of material are connected together by way of a corrugated core. Such a fabricated sheet could be made in any suitable material and may even be made of a suitable corrugated cardboard or the like that has been adequately treated to provide appropriate moisture or chemical resistant properties to the tubular element.

Each of the channel shaped components may thus be formed by cutting, typically die cutting, a sheet of the chosen material to the shapes illustrated in FIG. 7 so as to provide a first flat component (9) having two parallel fold lines (18) defining the central web (11) and flanges (13) and a second component (10) having two parallel fold lines (19) defining the associated central web (12) and flanges (14). The fold lines can be formed in any manner that is appropriate to the material from which the sheet is made.

Thus, in the case that thermoplastic material is used, the fold lines can be formed by heating the sheet material along these lines to soften it and then forming the required bends to form the channel shaped construction. The exact bending procedure can be varied widely and it is considered to be most expeditious for all lines of bend to be heated at the same time followed by bending of the sheet to form the channel shaped component that can be held in a jig while it cools and sets. Alternatively, the bends may be formed by mechanical deformation along the bend lines, typically using a vice like forming jig.

Alternatively, in the event that the sheet material has appropriate properties, the fold lines can simply be formed by mechanically crushing the composite material along the fold lines to render it substantially “hinged”. This arrangement is preferred in the event that the components are to be stored in a flat condition for erection and assembly at a subsequent time. It is to be mentioned that in this event, the flanges may well be preferably adhesively secured together in the erected condition and in order to facilitate this, areas of pressure sensitive adhesive could be applied to one or more appropriate surfaces of the flanges and covered with a removable cover strip pending assembly of the components to form a completed tubular element.

It is important to note that, in all instances, the fold lines (18, 19) are all made at: right angles to the direction in which the stiffening ribs or strengthening webs extend so that, in the operative orientation, the stiffening ribs or strengthening webs extend vertically and transverse to the length of the tubular element. This provides strengthening in the vertical direction in which support is required. It will also be understood that, in view of the fact that both of the sidewalls of the composite tubular element are of double thickness, additional strength is provided to support the weight of material within the bag at the relevant locations.

In a manner similar to that described in the published international patent application referred to above, the tubular elements of this invention are provided, at one end thereof, with extensions (20, 21) that are operatively bent outwards to extend at generally right angles to the associated wall of the tubular element so as to form protective flanges. In this embodiment of the invention the extensions are provided at the ends of the web and flanges of the narrower of the two channel shaped components so that the extensions (21) to the flanges cover the exposed ends of the flanges (14) of the outer channel shaped component and the extension (20) to the web extends operatively upwards.

Numerous variations may be made to the embodiment of the invention described above without departing from the scope hereof. In particular, the material from which the tubular elements is fabricated can be varied widely although it is preferred that it has reinforcing ribs or webs extending in a direction transverse to the length of the element itself. 

1. A bulk bag having flexible side walls; a bottom wall configured to define, with the sidewalls, a generally rectangular shape of bag; and a pair of laterally spaced generally flexible sleeve formations associated with the bottom wall and wherein each of the sleeve formations operatively receives a generally rigid tubular element of generally rectangular cross-sectional configuration such that the two tubular elements may receive the tines of a forklift truck, in use, wherein each tubular element is composed of two operatively generally horizontal elongate channel shaped components each having a pair of opposed side flanges and a central web interconnecting the side flanges and wherein one channel shaped component is inverted relative to, and fits within, the other to define said tubular element that has a pair of opposed composite side walls each consisting of two overlapping side flanges.
 2. A bulk bag as claimed in claim 1 in which the side flanges of the channel shaped components each have a series of spaced parallel ribs or strengthening webs extending up the height of the channel from the central web to the free edges of the flanges thereof.
 3. A bulk bag as claimed in claim 2 in which each channel shaped component is made from cut and folded sheet material that consists of two spaced parallel walls interconnected by an intermediate core that defines a series of spaced parallel stiffening ribs or strengthening webs.
 4. A bulk bag as claimed in claim 3 in which the intermediate core includes a series of parallel webs of material that are integral with the two spaced parallel walls.
 5. A bulk bag as claimed in claim 3 in which the intermediate core is defined by one or more corrugated layers bonded to the two spaced parallel walls.
 6. A bulk bag as claimed in claim 2 in which the corners of each channel are defined by generally right angled folds in the sheet material wherein the folds extend at right angles to the series of parallel stiffening ribs or strengthening webs.
 7. A bulk bag as claimed in claim 1 in which the overlapping flanges of the two channel shaped components are secured together by suitable means selected from adhesive, solvent bonding, and, in appropriate circumstances, thermal welding of the flanges together at a predetermined plurality of sites spread over the area of overlapping of the flanges.
 8. A generally rigid tubular element suitable for installation in a flexible sleeve formation on a bulk bag as claimed in claim 1, the tubular element being composed of two operatively generally horizontal elongate channel shaped components each having a pair of opposed side flanges and a central web interconnecting the side flanges and wherein one channel shaped component is inverted relative to, and fits within, the other to define said tubular element that has a pair of opposed composite side walls each consisting of two overlapping side flanges.
 9. A generally rigid tubular element as claimed in claim 8 in which the channel shaped components each have a series of spaced parallel ribs or strengthening webs extending up the height of the channel from the central web to the free edges of the flanges thereof.
 10. A generally rigid tubular element as claimed in claim 8 in which the tubular element is in kit form and comprises two cut blanks of sheet material configured to define fold lines along which the material can be folded to form the channel shaped components of the tubular element. 